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Usama F. Zaineldeen 《Journal of African Earth Sciences》2011,59(2-3):323-335
This paper presents the first paleostress results obtained from displacement and fracture systems within the Lower Eocene sediments at Jabal Hafit, Abu Dhabi Emirate, UAE. Detailed investigation of Paleogene structures at Jabal Hafit reveal the existence of both extensional structures (normal faults) and compressional structures (strike-slip and reverse faults). Structural analysis and paleostress reconstructions show that the Paleogene kinematic history is characterized by the succession of four paleostress stages. Orientation of principal stresses was found from fault-slip data using an improved right-dihedra method, followed by rotational optimisation (TENSOR program).The paleostress results confirm four transtensional tectonic stages (T1–T4) which affected the study area. The first tectonic stage (T1) is characterized by SHmax NW–SE σ2-orientation. This stage produced NW–SE striking joints (tension veins) and E–W to ENE–WSW striking dextral strike-slip faults. The proposed age of this stage is Early Eocene. The second stage (T2) had SHmax N–S σ2-orientation. N–S striking joints and NNE–SSW striking sinistral strike-slip faults, E–W striking reverse faults and N–S striking normal faults were created during this stage. The T2 stage is interpreted to be post-Early Eocene in age. The third stage (T3) is characterized by SHmax E–W σ2-orientation. This stage reactivated the E–W reverse faults as sinistral strike-slip faults and created E–W striking joints and NE–SW reverse faults. The proposed age for T3 is post-Middle Eocene. During the T3 (SHmax E–W σ2-orientation) stage the NNW-plunging Hafit anticline was formed. The last tectonic stage that affected the study area (T4) is characterized by SHmax NE–SW σ2-orientation. During this stage, the ENE–WSW faults were reactivated as sinistral strike-slip and reverse faults. NE–SW oriented joints were also created during the T4 (SHmax NE–SW σ2-orientation) stage. The interpreted age of this stage is post-Middle Miocene time but younger than T3 (SHmax E–W σ2-orientation) stage. 相似文献
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敞开酸溶-电感耦合等离子体光谱法测定钨矿石和钼矿石中微量元素 总被引:4,自引:4,他引:0
钨矿石和钼矿石具有丰富的共生或伴生元素,检测共生或伴生元素的含量有利于矿产资源的综合利用.在国家标准方法中钨矿石和钼矿石的共生或伴生元素含量是按元素分别检测,效率很低.本文在敞开体系中用盐酸+硝酸+氢氟酸+高氯酸消解样品,以7%盐酸溶解盐类,电感耦合等离子体发射光谱同时测定钨矿石和钼矿石中铋、钴、铜、锂、镍、磷、铅、锶、钒、锌等10种微量元素.选定了各元素的分析谱线和光谱级次,采用离峰背景校正法消除背景干扰,干扰元素校正系数法消除元素间的谱线重叠干扰.方法检出限为1.43 ~ 18.8 μg/g,加标回收率为90% ~ 110%.经钨矿石和钼矿石标准物质分析验证,测定结果与标准值基本吻合,方法精密度(RSD,n=10)小于8%.该方法克服了碱熔引入大量碱金属元素以及可能引入杂质的缺陷,又不用处理钨酸和钼酸沉淀,能快速测定钨矿石和钼矿石中微量共生或伴生元素. 相似文献
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Yun Yang Jianfeng Wu Xiaomin Sun Jichun Wu Chunmiao Zheng 《Environmental Earth Sciences》2013,70(6):2481-2494
Two primary goals of a multi-objective evolutionary algorithm (MOEA) for solving multi-objective optimization problems are to find as many nondominated solutions as possible toward the true Pareto front and to maintain diversity of Pareto-optimal solutions along the tradeoff curves. However, few MOEAs can achieve these two goals concurrently. This study presents a new hybrid MOEA, the niched Pareto tabu search combined with a genetic algorithm (NPTSGA), in which the global search ability of niched Pareto tabu search (NPTS) is improved by the diversification of candidate solutions that arose from the evolving population of nondominated sorting genetic algorithm-II (NSGA-II). The NPTSGA coupled with a flow and transport model is developed for multi-objective optimal design of groundwater remediation systems. The proposed methodology is then applied to a large field-scale groundwater remediation system for cleanup of large trichloroethylene plume at the Massachusetts Military Reservation in Cape Cod, Massachusetts. Furthermore, a master-slave (MS) parallelization scheme based on the Message Passing Interface is incorporated into the NPTSGA to implement objective function evaluations in a distributed processor environment, which can greatly improve the efficiency of the NPTSGA in finding Pareto-optimal solutions to the real-world applications. This study shows that the MS parallel NPTSGA in comparison with the original NPTS and NSGA-II can balance the tradeoff between the diversity and optimality of solutions during the search process and is an efficient and effective tool for optimizing the multi-objective design of groundwater remediation systems under complicated hydrogeologic conditions. 相似文献
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针对近年极端灾害性气候频发的现状,对暖冬影响下无锡站降雨年际变化趋势、历史演变特征和近几年水文预报情况进行了分析。结果表明:在暖冬影响下,无锡站降雨年际间呈现出干旱—湿润周期性变化的特征,具有水文旋回的性质,在太湖地区有代表性,可作为该时段的降雨预报模型;该模型打破了年际降雨无规律的传统思维定式,与历史演变法相结合,能提高预报效率与精度;水文旋回的发现和降雨预报模型的建立,可推动水文气象长期预报与气候展望研究。 相似文献
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随着地源热泵技术的推广应用,浅层地温能作为新型可再生资源得到了重视,对浅层地温能的资源评价业已展开。目前,从浅层地温能赋存地区的地质特点出发,分析其资源可开采量的研究尚不多见。重点介绍了浅层地温能可开采资源量的常规评价方法,并针对苏北平原区的地质特点,分析了在苏北平原区的具体地质特征下不同评价方法的适用性,得出了地下水式地源热泵可开采资源量的适宜评价方法为地下水量折算法;地埋管式地源热泵可开采资源量的适宜评价方法为换热量现场测试法;通过对本地区的工程案例分析,验证了上述2种方法在苏北平原区浅层地温能可开采资源量评价中能取得较高的精度。 相似文献
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